Archive for December, 2010

These are the closing paragraphs from the chapter (11) of Dr Richard Dawkins’ The Greatest Show On Earth: The Evidence for Evolution on how the evidence of our evolution is written all throughout our anatomy.

 

“Williams goes on to quote another Australian colleague, who shares the national gift for chucking a bonzer phrase, on the Ichneumonid //that one is as odd to type as it is to pronounce// wasps, whose designer, if there were one, ‘must have been a sadistic bastard.’ Darwin, although he visited Australia as a young man, expressed the same sentiment in staider, less antipodean //yeah that one i had to look up–no im not posting the definition// terms: ‘I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars.’ The legendary cruelty of ichneumon wasps (also the related digger wasps and tarantula wasps) is a leitmotif which will recur in the final two chapters of the book.

 

I find it hard to articulate what i am about so say, but it is something that I have been thinking for a while, and it came to a head during that memorable day of the dissection of the giraffe. When we look at animals from the outside, we are overwhelmingly impressed by he elegant illusion of design. A browsing giraffe, a soaring albatross, a diving swift, a swooping falcon, a leafy sea dragon invisible among the seaweed, a sprinting cheetah at full stretch after a swerving, pronking gazelle – the illusion of design makes so much intuitive sense that it becomes a positive effort to put critical thinking into gear and over come the seduction of naive intuition. thats when we look at animals from the outside. When we look inside, the impression is opposite. Admittedly, an impression of elegant design is conveyed by simplified diagrams in textbooks, neatly laid out and colour-coded like an engineer’s blueprint. but the reality that hits you when you see an animal opened up on a dissecting table is very different. i think it would be an instructive exercise to ask an engineer to draw an improved version of, say, the arteries leaving the heart. i imagine the result would be something like the exhaust manifold of a car, with neat line of pipes coming off in orderly array, instead of the haphazard mess that we actually see when we open a real chest.

 

My purpose in spending a day with the anatomists dissecting a giraffe was to study the recurrent laryngeal nerve as an example¬† of evolutionary imperfection. but i soon realized that, where imperfection is concerned, the recurrent laryngeal is just the tip of the iceberg. the fact that it takes such a long detour drives the point home with peculiar force. that is the aspect that would finally provoke a Helmholtz to send it back. bu the overwhelming impression you get from surveying any part of the innards of a large animal is that it is a mess! not only would a designer never have made a mistake like that nervous detour; a decent designer would never have perpetrated anything of the shambles that is the criss-crossing maze of arteries, veins, nerves, intestines, wads of fat and muscle, mesenteries and more. To quote the American biologist Colin Pittendrigh, the whole thing is nothing but a ‘patchwork of makeshifts pieced together, as it were, from what was available when opportunity knocked and accepted in the hindsight, not the foresight, of natural selection.’

 

theres so much more juicy stuff where that came from. please go buy it if you dont already have it, but do have at least an inkling of an interest in biology and anthropology.